package com.learning.demos;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.atomic.AtomicStampedReference;

public class ABADemo {
    static AtomicReference<Integer> atomicReference = new AtomicReference<>(100);
    static AtomicStampedReference<Integer> atomicStampedReference = new AtomicStampedReference<Integer>(100,1);

    public static void main(String[] args) {

        System.out.println("========以下是aba问题的产生===========");

        new Thread(()->{
            atomicReference.compareAndSet(100, 101);
            atomicReference.compareAndSet(101, 100);

        },"t1").start();

        new Thread(()->{

            try {
                TimeUnit.SECONDS.sleep(1);

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(atomicReference.compareAndSet(100, 2021)+"\t"+atomicReference.get());;
            atomicReference.compareAndSet(101, 100);

        },"t2").start();


        System.out.println("========以下是aba问题的解决===========");

        new Thread(()->{

            int stamp = atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName() + "\t第1次版本号" + atomicStampedReference.getStamp());

            try {
                TimeUnit.SECONDS.sleep(1);

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            atomicStampedReference.compareAndSet(100, 101, stamp, atomicStampedReference.getStamp() + 1);

            System.out.println(Thread.currentThread().getName() + "\t第2次版本号" + atomicStampedReference.getStamp());

            atomicStampedReference.compareAndSet(101, 100, stamp, stamp + 1);

            System.out.println(Thread.currentThread().getName() + "\t第3次版本号" + atomicStampedReference.getStamp());


        },"t3").start();

        new Thread(()->{

            int stamp = atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName() + "\t第1次版本号" + stamp);

            try {
                TimeUnit.SECONDS.sleep(3);

            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            boolean result = atomicStampedReference.compareAndSet(100, 2019, stamp, stamp + 1);
            System.out.println(Thread.currentThread().getName() + "\t最新实际版本号" + atomicStampedReference.getStamp());
            System.out.println(Thread.currentThread().getName() + "\t是否修改成功：" + result);

        },"t4").start();

    }
}
